This invention relates generally to excavating machinery and, more particularly, to tractor-mounted backhoe apparatus principally including an articulated boom mounted pivotally at one end to the rear of a tractor and a digging or trenching bucket carried by the boom at its free end. It is common in such backhoe apparatus that the articulated boom is comprised of a main arm or mast and a second arm, frequently referred to as a dipper stick, to which the digging bucket is pivotally attached. Thus, the main arm is fulcrumed at one end to a tractor mounting and at its free end supports the second arm of the boom through a horizontal pivot. The bucket, in turn, is mounted to swing, via a further horizontal pivot, at the free end of the second arm (dipper stick). In such arrangement vertical movement of the bucket is commonly accomplished through the use of hydraulic drives (cylinders and piston-type drive rods). A first cylinder and rod drive combination acts between the fulcrumed-end of the main arm and a pivot on the upper end of the second arm to swing the latter toward and away from the tractor. A second cylinder and rod drive combination is fastened at one end to the upper portion of the second arm and at the other end to the bucket to rock or curl the bucket about the horizontal pivot connecting the bucket to the second arm.